Justice Gödel Conder argues that RIM only showed people a dummy device and has yet to make an actual Playbook:

The PlayBook was never demoed at the Live Announcement. The dude is supposedly holding the device in his hands and he doesn’t touch the screen once. Let me repeat that. He never touches the device once! The screen never changes and it never gets dark. I cant help but wonder if he’s just holding a dummy (plastic) device.

He goes on to compare this with how Apple handled the iPad announcement – allowing everyone to play with the device and showing it in operation over Jobs’ shoulder. Interesting, if true this most likely means the device will ship late and not work as well as shown in the videos.